LIVERPOOL, England (Reuters) - Jeremy Corbyn was re-elected leader of Britain's opposition Labour Party on Saturday and called for unity after ending a "coup" by more centrist lawmakers who say his left-wing agenda can never deliver victory at the polls.

The veteran campaigner's triumph, by 313,209 to 193,229 votes, over challenger Owen Smith cements his authority over the divided party and will fuel a drive further left - a move many lawmakers say will see them out of power and allow the ruling Conservatives free rein over Britain's divorce from the EU.

Welcoming the result which handed him a larger share of the vote than his first leadership victory last year, Corbyn called on lawmakers and members at the party's annual conference in the northwestern city of Liverpool to come together to fight the Conservative Party and bring "real change" to Britain.

"Elections are passionate and often partisan affairs, things are sometimes said in the heat of the debate ... which we sometimes later come to regret. Always remember in our party we have much more in common than that which divides us," he said to roars from the crowd of largely his supporters.

"Let's wipe that slate clean and get on with the work we have got to do as a party together," he said, moving to ease fears that his re-election will widen the divide between the Labour Party's left and center-left wings and that he may trigger moves to force centrist lawmakers from the party.

His victory marks the next phase in a battle for control of the Labour Party.

In power for 13 years until 2010, Labour was dealt a crushing blow by the Conservatives five years later after they cast doubt on whether the party's left-wing policies would protect the economy.

The ruling party, under new Prime Minister Theresa May, still leads by seven percentage points in opinion polls and looks set to plot Britain's exit from the EU largely unopposed.

ELECTION VICTORY

Corbyn told the conference his anti-austerity policies had attracted thousands to Labour, helping to almost treble its membership to make it western Europe's largest, and he was ready to lead a more democratic party to election victory in 2020.

But he faces an uphill battle to win over those who voted Labour at the last election but then supported Britain's exit from the EU, after a YouGov poll showed more than half of them have now abandoned Labour.

He also has to convince many Labour members of parliament, some of whom decided not to attend the annual conference, that his left-wing policies, such as renationalisation and campaigning against nuclear weapons, can have broad appeal.

"The words are conciliatory but we need to have practical ways to put things back together and that is what we will wait to see," one senior Labour member of parliament, who declined to be named, told Reuters after the result.

Corbyn, 67, attracts a devoted following, but his election to leader last year on a wave of enthusiasm for change also unleashed a backlash against centrist lawmakers where personal attacks, allegations of anti-Semitism and abuse left little room for debate over policy.

Several in the party who once supported his candidacy as a chance to harness a growing disaffection for 'establishment politics' across Europe now rue the day they backed him.

But Corbyn tried to smooth over these divisions, calling the party "our Labour family".

"My responsibility as Labour leader is to unite this party ... but it is also the responsibility of the whole party ... to work together and respect the democratic choice that has been made," he said in his speech.

Centrist lawmakers say now they need to take stock, with some pushing to regain some control of the party machinery and boost groups promoting more center-left policies.

"It is an understatement to say that this is not the result that many of us wanted but all of us have now got to make an individual decision about how best to serve the Labour Party and how best to make the opposition effective," Labour member of parliament John Woodcock said.

Gareth Thomas, who nominated Corbyn for last year's leadership contest only to vote for a more centrist candidate, told Reuters: "Labour will now have to unite to focus our attack on Theresa May's Tory (Conservative) Party."

But for Corbyn's supporters, his re-election gives them what some describe as their one chance to make Labour a socialist party.

"This is a fantastic result," Jon Lansman, head of a pro-Corbyn campaign group, told Reuters. "What a great base for Labour to get back into government to rebuild and transform Britain."

(additional reporting by James Davey in London, editing by Jane Merriman)